Stitch formation



Dec. 11, 1962 G. B. ARMSTEAD, JR

STITCH FORMATION 2 sheets-sheet 1 Filed Nov. 18, 1959 *Msli Dec. l1, 1962 G. B. ARMsTEAD, JR 3,067,706

STITCH FORMATION Filed Nov. 18, 1959 2 sheets-sheet 2 my. s.

@aired States This invention relates to stitch formation and more particularly to an improved form of compound chain stitch particularly adapted to join plies of work material along parallel laterally offset edges.

One object of the invention is to provide a compound chain stitch for joining work material where parallel offset edges of the work material portions in overlapped or overlying relationship do not show through the stitching.

Another object of the invention is to provide a compound chain stitch seam for joining work material in the above relationship in `which the seam possesses substantial strength while being highly elastic in a direction parallel to the seam.

Still another object is to provide a compound chain stitch seam for joining work material in the above relationship which minimizes chaing when the seam is abraded as by washing.

Other objects and features of the invention will become apparent by reference to the following specification taken in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is a perspective view, partially in cross-section, showing a stitch formation embodying the present invention applied to two plies of work material;

FIG. 2 is a View similar to FiG. 1 showing the two plies of work material in FIG. 1 hinged into a subsequent formation with the stitch of FIG. 1 applied thereto;

FIG. 3 is a view similar to FIG. 1 showing a modified form of the stitch formation; and,

FIG. 4 is a View similar to FIG. 2 with the stitch formation of FIG. 3 applied to the work material.

The stitch formation of the present invention is adapted to be produced on a Morrow overedge sewing machine of well-known construction. During the formation of the stitch, the two plies of fabric to be joined are fed through the machine in the relationship shown in FIG. l wherein the uppermost ply of work material is located with its edge 12 projecting outwardly beyond the corresponding edge 1d of the lower ply 16. Edges 12 and '14 of the respective plies are thus located in a parallel laterally offset relationship. Since the major portions of both plies of fabric 11i and 16 are located upon the same side of the edges to `be joined, the stitch formation may be applied to plies of fabric having a width-ie. rightto-left dimension in FIG. 1which is not limited by dimensions of the sewing machine.

The stitch includes a first continuous needle thread 18 which is formed by the machine into a first series of fabric penetrating loops such as 20 which penetrate both plies of fabric at spaced points of penetration 22 which lie along a line parallel to and laterally offset from the edges of the plies of fabric to be joined. Each loop Ztl' passes downwardly through both plies of fabric and is extended outwardly and upwardly to locate bight portion 24 of each loop 2% adjacent the edge 12 of the uppermost ply of fabric.

A second needle thread 26 is formed into a second series of fabric penetrating loops 28 which, in the FIG. 1 embodiment, penetrate both plies of fabric at penetration points Sti laying along a line located between the line of peneration points 22 and edge 12. Each of the second series of loops 28 passes downwardly from its arent ice penetration points 30 through both plies of fabric and is extended outwardly and upwardly to locate the bight portion 32 of each loop 28 adjacent the edge 12 of the uppermost ply of fabric. As indicated by the cross-section of FIG. 1, each penetration point 22 of the first series of loops 2@ is approximately in lateral alignment with a corresponding penetration point 30l of a loop of the second series. `Bight portions 24 and 32 of laterally aligned loops of each series are located adjacent each other as indicated in FIG. l.

A covering thread 34 is formed into a third series of loops 36 passing through contiguous bight portions 24 and 3-2 of a loop 26' of the first series and the laterally aligned loop 28 of the second series. Bight portion 38 of each loop 36 of the covering thread extends around the next adjacent loop 28 of the second series at its point of fabric penetration 30. In so doing, the bight portion 38 of each loop 36 of the covering thread is disposed between the uppermost surface of upper ply 10 and adjacent runs 40 of the second needle thread 26.

In the usual case, the desired iinal relationship between the two plies of work material is that shown in FIG. 2 and the FIG. 1 relationship is used only as a manu-facturing convenience to place the stitches in the two plies of material.l After the stitches have been placed as in FIG. l, lower ply 16 is hinged about its edge 14 to shift into the relationship shown in FIG. 2. At the completion of this hinging movement, that surface 42 of the lowermost ply 16 which was the lowermost surface in the FIG. 1 relationship becomes the uppermost surface of ply 16 in the FIG. 2 relationship. This .action serves -to locate a portion of each loop 28 of the second thread between the overlapped portions of the respective plies 10 and 16.

As best seen in FIG. 2, each of the ed-ges 12 and 14 of the respective plies is lsubstantially fully protected or :shielded by the arrangement of the threads in the completed stitch. 'I'he edge 12 is protected by the runs of covering thread 34 which run substantially along edge 12 between adjacent bight portions 24 and 32 of the loops of the first and second series. The edge 14 is substantially protected by a portion of loops 20 of the first thread and a portion o-f loops 28 of the second thread. As well as protecting the edge of the fabric, these edge covering loop portions likewise tend to minimize chafling at the seam where the stitch is employed in the formation of garments such as corsets.

This complete seam is readily adaptable to the manufacture of elastic garments such as corsets since it is highly elastic in directions parallel to the seam. The binding action exerted by the loops 28 and the cooperating loops 36 of the covering thread labout the overlapped section of the work pieces achieves an extremely `strong seam.

In FIGS. 3 and 4 a modified stitch formation is disclosed which is generally similar to the stitch formation of FIGS. l and 2 but differs in that the second needle thread does not penetrate the lower ply of material. As in the previous case, the stitch formation shown in FIGS. 3 and 4 is formed from three continuous threads.

The modified form of seam includes a tirst continuous needle thread 118 formed into a first series of loops 120 which pass downwardly through both plies of material and 116 at penetration points 122 as in the previously described embodiment. The stitches are placed in the respective plies by feeding the plies through an overedge sewing machine with the edge 112 of the upper ply 110 projected outwardly beyond and in parallel lateral offset relationship to the corresponding edge 114 of the lower ply. Bight portions 124- of loops 120 are located adjacent edge 112.

A second continuous needle thread 126 is formed into a second series of fabric penetrating loops 128 which spec/,roe

penetrate only the upper portion of work material at penetration points 130 lying on a line located between the line of penetration points 122 and edge 112. Penetration points 138 are also located so that loops ZS project downwardly through points 130 just clear of edge 114 of the lower ply H6. Bights 132 of loops 128 are, as in the previous case, brought out to edge 112. and located adjacent the bights 124 of the laterally aligned loops 12) of the first series. Covering thread 134 is formed into a third series of loops 136 in exactly the same fashion as described above in connection with the FIGS. 1 and 2 embodiment so bight portions lSS lie between upper ply il@ and runs iid-tl of the second thread at penetration points 130.

As in the previous case, the completed seam usually finds the lower ply H6 being hinged into the FIG. 4 position. The completed seam as shown in FIG. 4 ditfers from the first embodiment in that loops 128 pass along the lower surface of upper ply 11i) and do not penetrate lower ply 116 as in the previous embodiment. The completed seam of FIGS. 3 and 4 possesses substantially the same shielded and elastic characteristics of the seam of FiGS. 1 and 2 and, in fact, is somewhat less susceptible to chafiing since loops 28 do not project from the inner (lower in FIG. 4) surface of the material. Some strength is sacrificed by not passing loops 128 through the lower ply, however, the seam of FIGS. 3 and 4 possesses adequate strength for most applications.

While two exemplary embodiments of the invention have been described, it will be apparent to those skilled in the art that the disclosed embodiments may be moditied. Therefore, the foregoing description is to be considered exemplary rather than limiting, and the scope of the invention is that defined in the following claims.

I claim:

l. A chain stitch seam joining two portions of work material with adjacent edges of said portions secured in overlapped parallel offset relationship comprising a pair ot continuous needle threads formed into two series of loops, one of said series of loops penetrating one of said portions of material at spaced points lying along a line spaced a first distance from the edge of said one of said portions and penetrating the other of said portions along a line adjacent said edge of said one portion, the other series of loops passing through penetration points lying at spaced points along a line located between the first mentioned line and the edge of said one portion, each loop of said other series lying between the overlap between said two portions, each loop of both series having a bight portion disposed adjacent said edge of said one portion, and a covering thread formed into a corresponding series of loops passing through the bight portion of a loop of said rst series and the bight portion of a loop of said second series adjacent the edge of said one portion, each of said covering thread loops having a bight portion looped around a succeeding loop of said second yseries at the penetration point of said succeeding loop of said second series.

2. A chain stitch seam joining two portions of work material in overlapped face-to-face engagement with each other with adjacent edges of the respective portions secured in parallel laterally ofiiset relationship comprising a first continuous needle thread formed into a first series of material penetrating loops, each loop of said first series penetrating both portions of work material by passing downwardly from points of penetration on the upper surface of the uppermost of said portions lying at spaced positions along a line laterally offset a first distance from the edge of the uppermost of said portions and passing upwardly through the other of said portions to project upwardly adjacent the edge of said one porvtion, a second continuous needle thread formed into a second series of material penetrating loops passing downwardly from spaced points of penetration lylng along a second line intermediate said first line and said edge of said uppermost portion and passing between the overlapped faces of the two portions, the points of penetration of said second series of loops being in substantial lateral alignment with the points of penetration of said f rst series of loops, the bight portion of each loop of said first series and the bight portion of the laterally aligned loop of said second series being located adjacent each other near the edge of said uppermost portion, and a covering thread formed into a third series of loops, each loop of said third series passing through the bight portion. of a loop of said second series and the bight portion of the loop of said first series laterally aligned therewith and extending across the upper surface of said upper portion to a bight portion looped around a succeeding loop of said second series at its point of penetration.

3. A chain stitch seam as defined in claim 2 wherein each loop or" said second series passes downwardly across the edge of the lowermost portion and penetrates said lowermost portion of work material to pass upwardly therethrough.

4. A chain stitch seam as defined in claim 3 wherein said uppermost portion of material projects outwardly beyond the lowermost portion of material, the loops of said first and said second series passing along the lower surface of said lowermost portion of material between their respective points of penetration and bight portions.

5. A chain stitch seam as defined in claim l wherein said portions of work material are overlapped with each other with said edge of said uppermost portion overlying the upper surface of the lowermost portion of material, each loop of said first series extending below the lower surface of said uppermost portion and the lower surface of said lowermost portion and penetrating upwardly through the lowermost portion of material to locate its bight adjacent the edge of said uppermost portion, each loop Yof said second series passing downwardly through said uppermost portion, passing along the lower surface of said lower portion, penetrating said lower portion by passing upwardly therethrough and extending along the upper surface of said lower portion between said overlapped portions of work material to said edge of said uppermost portion.

6. A chain stitch seam joining two portions of work material with respective edges of said portions secured in parallel overlapped relationship comprising a first continuous needle thread for-med into a first series of loops passing downwardly through the uppermost portion of material at spaced penetration points lying along a line spaced from the edge of said uppermost portion by a distance greater than the overlap between said portions, cach loop of said first series passing laterally beneath both of said portions and upwardly through the lowermost of said portions in substantial alignment with the edge of said uppermost portion to locate the bight of the loop of the first series adjacent said edge of said uppermost portion, a second continuous needle thread formed into a second series of loops passing downwardly through said uppermost portion at spaced penetration points lying along a line spaced from the edge of said uppermost portion by a distance substantially equal to the overlap between said portions, each loop of said second series having a bight located adjacent said edge of said uppermost portion in lateral alignment with a bight of a loop of said first series, and a continuous covering thread formed into a third series of loops, each loop of said third series passing through the bight of a loop of said second series and the laterally aligned bight of a loop of said first series, each loop of said third series extending across the upper surface of said uppermost portion to a bight looped around a succeeding loop of said second series at its point of penetration.

7. A chain switch seam as defined in claim 6 wherein the major portion of each loop of said second series passes laterally between said uppermost portion and said lowermost portion in the region of overlap.

8. A chain stitch seam as delined in claim 7 wherein each loop of said second series passes downwardly across the edge of the lowerrnost portion of material, laterally 5 beneath said lowermost portion to a second penetration point, upwardly through said second portion and laterally between said portions in the region of overlap.

9. A chain stitch seam as defined in clairn 7 wherein each loop of said second series is disposed entirely above 10 the lowermost portion of material.

References Cited in the tile of this patent UNITED STATES PATENTS 456,470 Borton Iuly 21, 1891 811,789 Onderdonk Feb. 6, 1906 875,594 Onderdonk Dec. 31, 1907 1,643,406 Finch Sept. 27, 1927 2,248,907 Lutz July 8, 1941 2,787,233 Walling Apr. 2, 1957 OTHER REFERENCES Federal Standard Stock Catalogue, March 1930. 

